Clutch mechanism



Dec. 15, 1942. T. F. THOMPSON 2,304,864

v CLUTCH MECHANISM Original Filed Dec. 16, 1938 2 Sheets-Sheet l Dec. 15,, 1942. T, F, T oM oN 2,304,864

CLUTCH MECHANISM Original Filed Dec. 16, 1958 2 Sheets-Sheet 2 Patented Dec. 15, 1942 GIiU-TCH MECHANISM TheodorcF-r Thompson, Des Moines, Iowa.

Qriginal application December 16, 1938, Serial No; 2461241. Divided and this applicationOotbber: 11, 1 940,. Serial No. 359,284

6. Claims.

This invention relates to apparatus for transmitting torque, foundespecially useful in its application to variable speed gearing, and more particularly to transmission gearing for motor vehicles. The application isa division of my prior application Serial No. 246,241, filed December 1 6, 1 938, which is in turn a continuation of my prior application Serial No; 2,047; filed J anuany 16, 1 935.

In: my prior applications I have described and claimed a transmission gearing for motor vehides in which the selection of certain speed ratios is automatically effected in response to variation in operating conditions, for example thespeed of the driven shaft, but in which provision is; made for the control of the initiation of: such automatic selection, so that. the. speedof. this coupling device. may" be fully understood,

it is-ragai'n. described herein. in. conjunction with other elements. of the. aforesaid. transmission mechanism. It; will. be. appreciated, however, that the; coupling device has: other uses, and. that the; speed; change: gearing is described merely to facilitate: an understanding; of the invention and its: utility Thus: it. is any object. of. the. invention. claimed herein to. provide av novel clutch. means? for selectively coupling two. coaxially' journaled members for rotation in such; manner. that; the torque transmitted through the members may be;- utilized to effect the; coupling.

A further object of. the. invention is the. pro.-

vision: ofa coupling; device. of the type described;

which is: sov constructed as to respond. readily andautomatically to operating. conditions; such as variationinspeed of one. of. the coupled elements, for establishing. the coupling: therebetween.

Further objects and features of. they invention will. be apparent from the: following description taken. in connection, with. the: accompanying:

drawings, in which:

Figure 1 is a. vertical longitudinal: sectional The arrangement is. suchthat inview of change speed gearing embodying the principlesof theinvention; I

Figure 2- is a plan view, partly in section, ofthe structure shown Figure 1 Figure 3 is a transverse sectional viewtaken substantially on the line- 3-3 of Figure 1';

Figure 4. is a transverse sectional view taken substantially on the. line- 4--4 of Figure. 1;

Figure .5 is a transverse: sectional view taken substantiallyon the line- 5--5 of- Figure I;

Figure 6 is a fragmentary: sectional view on the line 8-6 of" Figure- 4;

Figure. 7 isa detailed view of certain. elements shown in: Figure.- 2;

Figure. 8 is an enlarged fragmentary sectional view of certain. elements shown in Figure 1 and Figure 9 'is'a.side*elevati0n of the detail shown in Figure 8. I

In order to. facilitate: an understanding. of the invention, reference is. made to the preferred embodimentthereofi shown in the accompanyingdrawings: and specific language is: employed to describe. thev same. It will: nevertheless be appreciated; that: no; limitation of the scope of the invention 'is. thereby intended, various modifications. of; the: structure 'oliscloseol being: contemplated such. asiwould fall within. the province of one: skilled: in the art. to construct.

Figures 1 and 2 illustrate a selective-- change speed: gearing adapt'ed for use irr motor vehicles; the gearing being enclosedand supported in a housing I101 having adetachable cover plate I I. A separate compartment l3; preferably formed integrally with the housing M en'closes a control a device: for the. speed ratio selectingmechanism, this control: device being. described in more detail" hereinafter. I

Journaled in the forward end of the housing [0i is: adrive shaft I4 having a gear |5- on the rear end: thereof.. it driven shaft 24 is journaled in. the. rear end of the shaft M and extends lengthwise: of the" housing IO being journaled in; the rear end of the latter and being coupled to a propeller shaft l2 by means of a universal joint-59 The propeller shaft l2 may be connected through differential gearing, not shown, to the driving wheels of the vehicle in accordance with conventional practice.

A: countershaft [61513150 journaled in the housing. [0, thiscountershaft having formed" thereon gear" I18: meshes with the gear I5 on thedrive shaft I14 and the gears: 20 and I9 are in: mesh '1 respectively with gears 35 and. 41' which: are

known type of change speed gearing, falling within the class of gearing sometimes referred to as slidable key, change speed gearing, and the mode of operation will be obvious to one familiar with conventional practice. Thus it will be apparent that the gearss35,; 40, and 41 on the driven shaft 24 are continuously rotatedfrom the countershaft l6, which is in turn continuously rotated by the driving shaft I4. If the gear 35 be coupled to the driven shaft 24, torque will be transmitted at the lowest speed ratio which can be established. If the gear 41 is coupled to the driven shaft 24, the latter will be rotated at a somewhat higher, or intermediate, speed ratio. The coupling of the gear to the shaft 24 for concurrent rotation'establishes' a direct connection between the shafts I 4 and 24, which is the highest speed ratio afforded'by the gearing. Coupling the gear 40 to the driven shaft 24 will effect rotation of the latter in a direction reverse to that of the drive shaft 14.

The details of the structure thus far described form no part of the instant invention, and it will be apparent from the following description that the invention is applicable to many other types of transmission gearing. The invention is directed more particularly to improvements in the structure of the coupling devices.

It is preferable to associate the same type of coupling device with each of the several gears which are coaxial with the driven shaft 24, and for conveniencesimilar reference characters will clutch element on the shaft will result, and meshing engagement will be effected with the teeth of the complementary clutch element 28 to lock the gear 15 to the shaft 24.

It will be observed that in the coupling devices B, C, and D, the clutch elements 21 thereof 7 are connected to the shaft 24 through cam means or helical splines similar to those hereinbefore described but of opposite hand. .However, the clutch elements 26 of the coupling devices B and D are associated with complementary clutch elements 28 which are disposed at the rear side rather than at the forward side thereof, and

I these clutch elements will therefore function in be employed to describe those elements of these several coupling. devices which are similar in structure and function. The coupling devices, indicated generally at A, B, C, .and D are selectively operable to connect the shaft 24 for rotation with the gears 15, 35, 40, and 41 respectively.

In each instance :the coupling is preferably completed by positiveengagement of a slidable key or toothed clutch element 21, rotating with the shaft 24,-with a cooperating clutch element 28 formed on the associated gear. Thus referring to the coupling device A,,it' will be observed I that the clutch element 21, having external radial clutch teeth thereon, is provided with a helical splined connection 26 with the shaft 24. The gear 15 is provided with a complementary internally toothed clutch element 28 within which the clutch element 21 maybe slidably engaged. The

details of the splined connection between the be rotated in a clockwise direction with respect tothe shaft 24, as viewed fromthe forward end of the latter, forward "axial: movement of this the manner just described, on the application of torque thereto in a clockwise direction, to couple the gears 35 and 41 to the shaft 24. The clutch element 21 associated with the coupling device C- will move into meshing relation with its complementary clutch element 28 upon the application of torque to the clutch element 21 in a ciated clutch element 21, provided the shaft 24 is stationary or is rotating at a less speed than that of the gear in question. In other words, in

order to clutch the gear to the shaft, means con- .1 stituting in itself a clutch, acting between thegear and associated employed. j

Thus referring more particularly to Figures 3, 8, and 9, illustrating the structure associated with clutch element 21, maybe the coupling device A, it will be noted that an annular member 29 is secured to. a radial flange,

formed integrally with theytoothedqclutch ele-' -ment 28, which is in turn integral with the gear l5 and the shaft l4. A plurality of pawls 30 are pivotallysupported on the member 29 for rock-- ing movement about axes extending longitudinal lyof the transmission, these pawlsbeing positioned for engagement with the external toothed portion of the associated... clutchelement 21. Each of, the pawls 539 is provided with'a tail portion 3| having one side thereof beveled, as shown'in Figure 8. An annular collar 32 surrounds the member 29, and-this collar is displaceable axially by means of a fork 94 which partially embraces the collar so that the collar 32 may he slid axially and toward the right from the position in which it isshown in Figure 8 to a position in which it engages and embraces the tail portions 3| ofthe pawls 30., It will be appreciated that as the collar rides overthe beveled edge of the tail portions 3| of the pawls, such tail portions .will .be depressed and the nose por-" tions of the pawls will bemoved outwardlyftd disengage the pawls from the external teeth of the clutch element 21, and the pawls will be so retained until the collar .32isagain moved to the,

left to release the pawls. Each of the'pawls is normally urged into engagement with the clutch element 21 by means of a spring 42, but the nosev of each pawl is so formed that when the annular member 29 rotates :in a clockwise direction 7 with respect to the clutch element 21, the pawls will ride over the toothed portion of the clutch element withwhich they-cooperate.

The function of the several coupling device will now be readily understood; Thus, referring to the coupling device A, if the fo rk'94 be moved to the left from the position in which it is shown described it will be 3 in Figure 1 to the position of. Fi ure 8, the collar 32" will, be correspondingly displaced, and the pawlsfifiwill be released to. permit engagement thereof with, the external toothed. portion ofv the: clutch elemftnljlzj'l. If the shaft l4: issrotatinginy a" clqckis direction at a greaterspeedthanthe shaft 24, as is normally the case; immediately prior; to the, selection of a higher speed ratio, the clutch element 21 will thenbe rotated by the pawls 30 in a clockwise; direction with respect to the shaft 24, and by; reason of the helical splined,

connection, therebetween, the clutch element 21 will be displaced axially to the; left fromthe position-in which it is. shown in Figure. 8' and will engage the complementary clutch. element 28:? to lock the gear I 5 and shaft 14 to the' shaft; 24 for concurrent, rotation. i

The structure and function of the remaining coupling devices, may be precisely the same. Thus, immediately prior to the selection of the lowspeedratio by actuation of the coupling device- B, the shaft 24 is ordinarily stationaryrand the shaft l4 isrotating: in a clockwise direction. Consequently when the pawls 30 of the coupling device are released by the collar- 32' and engage with the external teeth of the clutch element: 2]., the latter will. be shifted to the; right to engage the complementary clutch element 28 carried by: the-gear 35, and the low speed ratio between the shafts l4 and 24: is. therebyestablished. Similarly, immediately prior to the selection of theintermediate speed; ratio, the shaft 24 is being driven from the countershaft through the gears 20. and, 35, and is therefore rotating at a, speed less than that of the gear 4;1, which isv being driven from the gear IS on the countershaft..

Consequently, when the pawls: 30 of the coupling device D are engaged with the. associated clutch element 2-! by displacement of the collar 32 to the rig-ht, the helical splined connection; between the clutch element 21 and the shaft. 24 will act. to displacethe clutch, element 21, to the right into engagement, with the complementary clutch element 28, whereby the gear 41 will be positively clutched to the shaft 24 to establish the intermediate speed ratio.

Atthis state in the progressive selection of ratios,the rotationa1 speed of the shaft 24" exceeds the rotational speed of the gear 35. Con.-

sequently the pawls. 3Bof the coupling device 13,.

associated with the gear 35, will ride over the external teeth of the associated clutch element 28. The cooperating toothed elements of the coupling device B are now disengagedby suitable means provided for the purpose. For example, one: or more coil tension springs I 09 may be connected between the clutch elements 21 associated with the coupling devices A and B, and between.

the clutch elements 2! associated with thecoupling devices C and D, these springs acting to withdraw each, of the clutch elements 21 when the: direction of torque between the associated gear and the shaft 24 is reversed by the selection of a higher ratio.

The coupling device A functions similarly, after the selection of the intermediate speed rati0,;,to effect direct coupling of the shafts l4 and 24. Thus immediately prior to such selection, the shaft 24 is rotating at a lower speed than the shaft I 4, and when the pawls 30 associated with the coupling device A are engaged with the clutch element 21 of that device, the latter is displaced to the-left to effect the desired direct ecu.- pling thepawls, 30 associated with the coupling; device D: rideover the associated clutchelement 2-1, andthe latter is withdrawn: from the complementary clutch. element: 28' by the action of the spring H10- Immediately prior tov the selection of the coupling device C, which effects reversal of the direction of rotation: of the shaft 24, the latter is ordinarily stationary while the gear 40 is rotating in a counterclockwise direction. Consequently when the pawls 3.0 of th coupling device 1 C are engaged with the associated clutch element 21, the latter is displaced to the left from the position in which it is shown in Figure l, to positively connect the gear ditto-the shaft 24 and to rotate the latter in the reverse direction.

If, when any one of the coupling devices A, B,

and- D has been rendered operative tocouple the associated gear to-theshaft 24, the motor is decelerated so that the gear in question tends to-rotate at a less speed than the shaft 24, the coupling device which is effected at the moment will be released, by disengagement of the cooperating clutch elements 2'! and 28 in the-manner hereinbefore explained, and the vehicle driving wheels will thereforebe disconnected from the motor. In

* other words, the effect will b the same as that t the Shaft 24.

It will be apparent that in lieu of the positive engagement afforded by the cooperation of the pawls 3% with the associated clutch elements 21, friction pawls engaging a continuous annular friction surface may beused, or some other friction type of coupling maybe employed between the gear and the associated clutch element Similarly, it is obvious that the positive toothed engagement between the several clutch elements 2'! and the cc-mplementary'cl'utch elements 2-8 is coupling devices A, B, C, and D be similar structure and function; it being possible tore-- place anyone or more of these coupling devices- This witha different type of coupling means. is of course particularly true of the coupling device C, which is operable in order to reverse the direction of rotation of the driven shaft and which therefore functions entirely independently of the remaining devices. However, the type of coupling device illustrated herein is particularly desirable since itpermits the-progressiveselection of speeds without interruption of the drive, and

thereby eliminates the necessity of operating the vmain vehicle clutch. when selection is effectedhousing it for limited; axial reciprocation is, a- .shift rod: 52, to which. are-secured thezshift forks, 9,5 and 96. Thus; displacement oftheT shift rod forwardly-from the central or "neutral position which it occupies in Figure 1 effects withdrawal of the collar 32 of the coupling device C from the associated pawls, whereby the gear 40 may be coupled to the shaft 24, in the manner hereinbefore described, to rotate the shaft in the reverse direction. Displacement of the rod 52 rearwardlyfrees the pawls 30 of the coupling device B, so that the gear 35 may be automatically coupled to the shaft 42, providing that gear is rotating faster than the shaft 24. Secured to the shift'rod 52 is, a bracket 55 which extends through a slot 56 in the cover plate. A Bowdenwire is connected between the outer end of the bracket 55 and an operating handle on the dash, or other part of the vehicle interior, so as to be readily accessible to the driver, whereby the gearing may be placed either in reverse or in low speed ratio in the manner hereinbefore explained and at the will or -the operator. r

A rod 14 is rotatably mounted in the housing In and extends longitudinally thereof and into the compartment l3, apinion 15 being secured to the rod 14 adjacent the rear end of the latter. A rack 16 is disposed in meshing relation with the pinion '15, being retained in engagement therewith by a roller Tl. At its lower end the rack 16 is pivotally connected to a bell crank lever. II, and the opposite arm of this lever carries a ment being suchthat these weights tend to move radially outward of the shaft 6|, as the latter is rotated, under the action of centrifugal force, such movement being resisted by coiled tension springs 6'! connecting each weight with the fulcrum of the opposite lever arm 65. Each of the lever arms 65 is provided, On the other side of the fulcrum therefor, with a finger 10 which engages with the collar 69. The shaft Si is rotated from the shaft 24 by means of worm gearing 60, 62.

- The structure just described constitutes a governor mechanism for rotating the shaft i4 through an angle which is determined by the speed of rotation ofthe driven shaft 24 of the transmission, and the mode of operation of this structure will be at once apparent. Details of the governor mechanism form no essential part of the present invention and may be modified as desired.

The fork 94 is carried by a boss 92 which is in turn mounted on the shaft 14 and isfreely reciprocable thereon. Immediately adjacent the boss 92 and secured tothe shaft 14, are collars 90 and 9|, the latter being shaped to form an axial closed cam, the collar90 being shaped to follow the cam surfaces thus afforded. It will be observed from Figure 7 of the drawings that as theshaft 14 is rotated, the collar 90 and fork 94 are reciprocated, the fork being thereby movable to either of two positi0ns. These two positions of the fork correspond to the two positionsof the collar 32 engaged by the fork, in one of which the collar disengages the pawls from the clutch element 21, and in the other of which the pawls are released to permit engagement thereof with the teeth of the clutch element.

A The shaft 14 also affords a support fora-boss 7 93 which ca rriesthe forkB'l, and this boss co operateswith collars 98 and 99fwhich; are-sc be displaced forwardly, to render the coupling deviceAefiective- The sequence of operations'performed by the structure'thus far described in bringing the vehicle from a standstill to direct drive or high I speed ratidmay be briefly described as rouows; After. the motor has beenlstartedftheBowderr' wire 51 is'first manually operated to release thepawls30 associated with the coupling device B and thereby to connectthe low-speed gear 35 i to the driven shaft 24. When a certainpredetermined vehicle speed is reached, the governor mechanismshown in Figure 5 has'rotated the shaft 14 to-an extent suflicientto release the pawls 30 associated with the coupling device D, 7 thereby to connect the intermediate speed gear 41 to the driven shaft 24, and the low speed gear 35 isautomatically disconnected from shaft 24 as hereinbefore explained. As the vehiclespeed further increases, the shaft "is rotated fur-w ther, the pawls 30 associatedwith the coupling device A are released, and thegear l5 and shaft M are directly connected to the shaft 24, thus:

establishing the highest ratio or direct drive. If theload on the vehicle increases while the gear ing is indirect drive, for example on ascending a steep grade, with the result that the vehicle speed is materially reduced, the governor mecha nism will rotate the shaft 14 in the'reverse-direction, and the pawls'30 associated with the can:

pling 'device' A will be withdrawn from the associated clutch element 21. If the operator then reduces the motor speed by closing the motor:

throttle, so that the "shaft tends tofrotate slower'than the shaft 24, the clutch'element 2-1 associated, with the coupling deviceA will be withdrawn from the clutch element 28 by the combined action of the helical splines onthe shaft 24 andthe spring I00. Openingof' the throttle thereafter-willserve to rotate the g'ear 41 faster than the shaft 24, and this gear will be coupled to the shaft as hereinbefore explained to re-establish the intermediate speed ratio. This" action is predicated on the assumption that the vehicle speed has not been reduced tosuch an extent that the collar ,32 associated withlthe' pawls 30 of the coupling device D has disengaged i these pawls from the cooperating clutch element 21; if the vehicle-speed is quite low,-the low speed coupling device B will be operated on opening of the throttle, as hereinbefore explained. The speed ratio selection is pre'ferabl made further dependent on the will of the operator by the provision ofadditional means responsive to 7 engine operation'for controlling the rotation of thefshaft l4, by'means of which the coupling devices Aand D are actuated. Thus aldiscr "is secured to the shaft 14, the periphery of the disc being recessed-as indicated at 19 and 80. A pawl 84 pivoted n a bracket is normally urged into engagement with the periphery of the di scfl8 by a spring 81. Formed integrally with the pawl is an arm 85 ex-tendinglaterally-of the compartment with the-arm 86. Thus when the s'hi-ftrod ment 1'3. A longitudinally extending rod 88, slidably supported wi'thin' th'e housing I 0, lies directly over the arm "86 and is provided adjacent the latter with a one-way pawl '89, the arrangement being such that when the rod 88 i'smoved to the left from the position in which it"is shown in Figure 6-, the pawl 89 will force the rod downwardly. On reciprocationof the rod 88 inthe opposite directionfthe pawl 89 will ride over the rod without depressing the same, assuming the position shown "in dotted "lines in Figure 6, and will again drop into th'e fu1l-line posi tion to the rear of the arm 86. The forward e-nd of the rod '88 is connected to the motor throttle, orto some actuating 'm'eans therefor such as the usual accelerator pedal, so that on each movement of the throttle from closed to open position, the rod 88 will be displaced forwardly and the arm 85 depressed.

When the shaft 14 is rotated by the governor mechanism to a position in which the pawls 39 associated with the coupling device D are released, the nose of the pawl 84 will drop into the recess '19, tolock the shaft 14 against further rotation. Thus the intermediate speed ratio will be maintained until the operator desires to establish directdrive, which he may do, provided the requisite vehicle speed has been reached, by

releasing the accelerator pedal and again "de-' pressing it, thus causing the rod 88 to depress the arm 85, disengage the pawl from the recess 19, and permit the disc 18 and shaft 74 to rotate to a position in which the nose of the pawl will engage the recess 80. When this point is reached, the pawls 38 associated with the coupling device A are released, and di-rect drive is "established.

As hereinbefore explained, if the vehicle speed is reduced after direct drive has been "established,

and the operator finds it=desi-rable to establish a lower speed ratio, he decelera'tes and then accelerates the motor. "When the accelerator pedal is thus released and againdepressed while the vehicle is ascending a grade at relatively slow speed, the pawl 84 will be released from the recess 80, and the governor mechanism effects rotation of the shaft 14 in a reverse direction until the pawl 84 falls in the recess 19, at which instant the intermediate speed-ratio is established, the high speed ratio being discontinued when the motor is retarded, as hereinbefore explained. In order to re-establish the low speed ratio, the operator must again release and depress the accelerator pedal to permit the disc 18 to rotate to the position in which it is shown in Figure 4 of the drawings. It will thus be seen that the selection of the several speed ratios, while progressing automatically in either direction in response to variation in vehicle speed, is at the same time largely under the control of the operator since such changes are initiated in response to motor operation.

Formed integrally with the bracket 55 is a laterally extending arm 82, the free end of the latter being arranged to overlie the lug 83 on the disc 18 when the vehicle is not running and the shift rod 52 occupies either the neutral or the reverse position. Thus the selection of intermediate or high speed ratios while the gearing is in reverse, or prior to the selection of the low speed ratio, is definitely prevented.

An upstanding arm 99 is formed integrally with the arm 82, the arm 99 being formed at its upper end with a hook-shaped or cam portion H32, as shown more particularly in Figure 6, for engage- Cal 52 is displaced to a neutral position, intermediate the positions in which the coupling devices B and C respectively are rendered operative, the

'arm 86 will be engaged and depressed by the hook-shaped portion 102, to release the pawl "84 from either of the recesses 19 or in which it may be disposed. Thus the disc 7-8 and the shaft T4 may be released for rotation by manual actuation of the Bowden Wire 51. The hook-shaped portion I02 is sufficiently long to permit of displacement of the shift rod 52 to a position in which the coupling device C is rendered operative toplace the gearing 'inreverse.

I While a speed controlled'governor is employed for effecting selection of the several speedy-ratios, it is obvious that the selection of speed may be effected in response to variation of other-charactofore proposed. Similarly, is apparent that the manual connection of the selecting mechanism to the accelerator pedal is only'one way of controlling the initiation of speed selection, it being feasible to employ other means for rendering the selecting mechanism dependent upon motor operation.

The term axial cam means as employedherein is intended to designate means having coacting surfaces of which one is inclined axially of the shaft, whereby on the occurrence of relative rotation between said surfaces, the parts with which the surfaces are associated are displaced axially of the shaft.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is: g

1. 'In mechanism for coupling a rotatable shaft and a coaxial element for concurrent rotation, the combination with a member supported for axial reciprocation and coaxial rotation withrespect to said shaft and element, axial cam means connec'tingsaid member and shaft, said member and element having coacting clutch means engageable on axial displacement of said member, and means operable to relatively rotate said member and shaft to effect such axial displacement of said member by said cam means, said last named means including a releasable connection between said element and said member, and speed responsive means driven by said shaft for operating said releasable connection.

2. In apparatus for transmitting torque, the combination with a rotatable driven shaft, of a driving gear supported for rotation on said shaft, means for operatively coupling said gear and shaft, said means including a member supported on said shaft for rotation and axial reciprocation with respect thereto, axial cam means acting between said member and shaft for effecting relative axial displacement thereof on the occurrence of relative rotation therebetween, cooperating clutch means associated with said gear and member engageable by axial displacement of said member in one direction, and means operable to rotate said member in the. direction of the desired rotation of said shaft only, and at a higher speed than said shaft, to engage said clutch means, said last named means including a device carried by said gear for engaging said member, and speed responsive means for rendering said device operative.

3. In apparatus for transmitting torque, the

combination with a rotatable driven shaft, of a driving gear supported for rotationon said shaft, means for operatively coupling said gear and shaft, said means including a member supported on said shaft for rotation andaxial reciprocation with respect thereto, axial cam means acting between said member and shaft for effecting rela, tive axial displacement thereof on the occurrence of relative rotation therebetween, cooperating clutch means associated with said gear and memberengageable by axial displacement of said member in one direction, and means operable to rotate said member in the direction of the desired rotation of said shaft only, and at a higher speed than said shaft, to engage said clutch, means, said last named means including a clutch device acting between said gear and said member, and

speed responsive means driven by said shaft for operating saidclutch device.

4.In apparatus for transmitting torque, the i combination with a rotatable driven, shaft, of a driving gear supported for rotation on said shaft, means for operatively coupling said gear and shaft, said means including a member supported on said shaft for rotation and axial reciprocation.

with respect thereto, axial cam means acting between said member and shaft for efiectingrelathan said shaft, to engage said clutch means,,

said last named means including a releasable ,pawl and ratchet device acting between said gea1 and said member, and axially, displaceable operating means associated with said pawl ,and'ratch- ,et device to effect the release and application of the latter.

5. In apparatus for transmitting torque, the combination with a rotatable driven shaft, of a driving gear supported for rotation on said shaft, means for operatively coupling said gear and shaft, said means including a member supported on said shaft forrotation and axialreciprocation with respect thereto, axial cam ,meansacting be tween said member and shaft for effecting relative axial displacement thereof on the; occurrence of relative rotation therebetween, cooperating clutch means associated with said gearand member engageable by axial; displacement of :said member in one direction, means operable to row tate said member in the direction of the desired rotation of said shaft on1y,-and'atzahigherspeed than said shaft, to engage said. clutch means,v

, whereby overrunning of saidgear' bysaid: shaft shaft for axially displacingsaid operatingmeans. 6. In apparatus for transmitting torque, the combination with a rotatable driven sh'aftfof a driving gear supported for rotation on said shaft,

effects displacement of saidwrnember in'the opposite direction to disengage said clutch means,

said last named means including -areleasable pawl and ratchet device acting;.b tween,said-gear and said member, axially displaceable operating 7.

means associated with said pawl and ratchet device to effect the release and application-ofr the latter, and speed responsive means driven by said means for operatively coupling said gear 'and shaft, said means including a membersupported onsaid shaft for rotation andaxial reciprocation with respect thereto, axial cam means actingbetween said member andshaft for effecting ,relative axial displacement thereof on the QCQur rence of relative rotation therebetween, cooperating clutch means associated with said gear and member engageable by axial displacement of said member in onedirection, means operable torotate said member in the direction of the desired rotation of saidshaft only, and at a higher speed than saidshaft, to engage said clutch means, said lastnamed means including'a releasablegpawl and ratchet device acting between said geary-and said member, and operating means a'ssociated with said pawl and ratchetdeviceto eifeetthe release and application of the latter; 1;;

THEODOltE R moMPsonQ 

